The present application is concerned with the area of gaseous effluent pollution control. More particularly, the invention is concerned with the gaseous effluent resulting from industrial processes, in particular, the application and drying of paint on substrates such as transportation vehicles as automobiles, trucks, and the like.
During various industrial processes, gaseous effluent is formed. Due to the increased concern with the atmospheric environment, various processes have been suggested to control the gaseous effluent introduced into the environment. Increased research and development has been undertaken, especially with respect to the effluent resulting from the application of liquid paints containing organic solvents to various substrates such as automobiles, trucks and the like. One such process is that described in U.S. Pat. No. 3,932,151, which relates to paint spray booth construction and control of excess atomized paint from the air in the vicinity of a spray-painting operation.
Another proposed solution to the problem of gaseous effluent control is a technique where the gaseous effluent is adsorbed onto a high surface area of carbonaceous substance, such as activated carbon. The difficulty with such a procedure is that when it came time to remove the adsorbed solvent, a vacuum stripping operation was employed, which therefore produced a hazardous condition in that the solvent was explosive at such vapor concentrations. To overcome this problem, water was applied to the activated carbon, thereby significantly decreasing the effectiveness of the activated carbon by substantially decreasing the surface area of the activated carbon. Such an approach is highly inefficient for large volumes of gaseous effluent.
In designing a process for the purification of gaseous effluent one must be particularly conscious of being able to re-claim the gaseous effluent in order to make the process economically desirable from an overall point of view.